Low parent engagement is frequently identified as a barrier to effective implementation of family-based childhood obesity prevention and control programs. A more nuanced understanding of factors affecting parent engagement is important for improving implementation and, ultimately, program efficacy. This qualitative study examined factors influencing parent engagement in a family-based childhood obesity prevention and control program. Semistructured interviews informed by the health belief model and the transtheoretical model were conducted with 22 predominantly Latina mothers following the scheduled conclusion of program activities. Spanish- and English-language interviews were transcribed, translated into English (if Spanish), coded, and summarized using established protocols. Differences between parents who attended at least two thirds of program activities and those who did not were examined. There were no significant demographic differences between parents who did and did not complete two thirds of program activities. Findings indicated that differences in parent engagement may be at least partially explained by differences in parental motivations for participating and in barriers and facilitators, such as children’s level of support and enthusiasm for the program. Parents were highly satisfied with the program content and the community health workers who delivered the program. This study adds to emergent literature regarding parents’ experiences in family-based childhood obesity prevention and control programs. Potential targets for improving program engagement are discussed.